Newton rate of temp. change

1. The problem statement, all variables and given/known data
A container of hot water at 80°C cools to 79°C in 15 seconds when it is placed in a room that is at 20°C. Use Newton's law of cooling to estimate the time it will take for the container to cool from 70°C to 69°C.
And still later, from 30°C to 29°C.